Messages

API which allows your app to publish simple messages and subscribe to receive those
messages from nearby devices.

The API performs its operations in an unauthenticated manner, so it does not require a
Google account. However, it requires that the developer has a project in the Google Developers Console with the following
prerequisites:

The message is only delivered to apps that share the same project id in the
Developer Console and have an active subscription. Create project identifiers and turn
on the Nearby API in the Google Developers
Console.

See Also

Note: Currently, this method only finds messages attached to BLE beacons. See
Beacons.

Subscribes for published messages from nearby devices in a persistent and low-power
manner. This uses less battery, but will have higher latency and lower reliability.
Notably, updates may only be delivered when the device's screen turns on (or when
Bluetooth turns on). The subscription will be retained after the client
disconnects.